— On Wednesday, Dec. 8, SpaceX will attempt the first-ever test flight of its Dragon capsule — a new spacecraft designed in the last decade to carry supplies and eventually humans to and from the International Space Station and other orbital destinations — and only the second ever test flight of its Falcon 9 two-stage launch vehicle.

Dragon's mission, which is the first demonstration for NASA's Commercial Orbital Transportation Services (COTS) program, will see it circle the Earth twice before re-entering and splashing down in the Pacific Ocean. If successful, the flight to 186 miles (300 kilometers) altitude will also mark the first time that a commercial company has recovered a spacecraft from orbit, a feat earlier achieved by only the government space agencies of the United States, Russia, China, India, Japan and Europe.

Onboard Dragon for this first flight is 600 pounds of ballast, as well as "thousands of patches," and badges for each of SpaceX's employees.

The launch was originally targeted to take place a day earlier, but on Monday, the company discovered cracks in the rocket's second stage engine nozzle. SpaceX repaired the bell-shaped Merlin Vacuum nozzle extension by trimming the thinnest portion of the niobium sheet alloy, which contained the cracks.

Departing from Space Launch Complex (SLC) 40 at the Cape Canaveral Air Force Station in Florida, the launch window Wednesday extends from 9:00 a.m. to 12:22 p.m. EST (1400 to 1722 GMT).